Charles Fernyhough has written extensively on the implications of Vygotsky's theory, particularly for the emergence of verbal mediation in the preschool and early school years. He has previously co-edited a four-volume collection of critical assessments of Vygotsky's work (1999). He has been involved in three major longitudinal developmental studies with samples in Cambridge, Stoke-on-Trent, and Stockton-upon-Tees, along with several studies of psychosis-like symptoms in healthy adults and children. Recent articles have included work on the neuropsychology of voice-hearing, the stress diathesi...